/** @file
  RISC-V Flattened Device Tree DXE module

  The Linux booting protocol on RISC-V requires the id of the booting hart to
  be passed as a0. Therefore the EFISTUB needs to get this information. Because
  it runs in S-Mode, it cannot get this information from mhartid. Instead we
  insert the id into the device tree, that the EFIFSTUB can read from the config table.

  Copyright (c) 2021, Hewlett Packard Enterprise Development LP. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent
**/

#include <Library/UefiBootServicesTableLib.h>
#include <Library/DebugLib.h>
#include <Library/HobLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/PcdLib.h>
#include <libfdt.h>

/**
  Fix up the device tree with booting hartid for the kernel

  @param DtbBlob The device tree. Is extended to fit the hart id.

  @retval EFI_SUCCESS           The device tree was success fixed up with the hart id.
  @retval EFI_OUT_OF_RESOURCES  There is not enough memory available to complete the operation.
**/
EFI_STATUS
EFIAPI
FixDtb (
  IN OUT VOID  *DtbBlob,
  IN     UINTN  BootingHartId
  )
{
  fdt32_t Size;
  UINT32 ChosenOffset, Err;

  DEBUG ((DEBUG_INFO, "Fixing up device tree with boot hart id: %d\n",
    BootingHartId));

  Size = fdt_totalsize(DtbBlob);
  Err  = fdt_open_into(DtbBlob, DtbBlob, Size + 32);
  if (Err < 0) {
    DEBUG ((DEBUG_ERROR,
      "Device Tree can't be expanded to accommodate new node\n", __FUNCTION__));
    return EFI_OUT_OF_RESOURCES;
  }
  ChosenOffset = fdt_path_offset(DtbBlob, "/chosen");
  fdt_setprop_u32(DtbBlob, ChosenOffset, "boot-hartid", BootingHartId);

  return EFI_SUCCESS;
}

/**
  Install the FDT passed in HOB into EFI system configuration table.

  @retval EFI_SUCCESS          Successfully installed fixed up FDT in config table.
  @retval EFI_NOT_FOUND        Did not find FDT HOB.
  @retval EFI_OUT_OF_RESOURCES There is not enough memory available to complete the operation.
**/
EFI_STATUS
EFIAPI
InstallFdtFromHob (VOID)
{
  EFI_STATUS         Status;
  EFI_HOB_GUID_TYPE *GuidHob;
  VOID              *DataInHob;
  UINTN              DataSize;

  GuidHob = GetFirstGuidHob (&gFdtHobGuid);
  if (GuidHob == NULL) {
    DEBUG ((DEBUG_ERROR, "Failed to find RISC-V DTB Hob\n",
      __FUNCTION__));
    return EFI_NOT_FOUND;
  }
  DataInHob = (VOID *) *((UINTN *) GET_GUID_HOB_DATA (GuidHob));
  DataSize  = GET_GUID_HOB_DATA_SIZE (GuidHob);

  Status = FixDtb (DataInHob, PcdGet32(PcdBootHartId));
  if (EFI_ERROR (Status)) {
    return Status;
  }

  Status = gBS->InstallConfigurationTable (&gFdtTableGuid, DataInHob);
  if (EFI_ERROR (Status)) {
    DEBUG ((DEBUG_ERROR, "%a: failed to install FDT configuration table\n",
      __FUNCTION__));
  }
  return Status;
}

/**
  Install the FDT from the HOB into the EFI system configuration table.

  @param ImageHandle     Image handle of this driver.
  @param SystemTable     Pointer to the System Table.

  @retval EFI_SUCCESS    FDT successfully installed into config table.
  @retval EFI_NOT_FOUND  Did not find FDT HOB.
  @retval EFI_OUT_OF_RESOURCES There is not enough memory available to complete the operation.

**/
EFI_STATUS
EFIAPI
InstallFdt (
  IN EFI_HANDLE                            ImageHandle,
  IN EFI_SYSTEM_TABLE                      *SystemTable
  )
{
  EFI_STATUS  Status;

  Status = InstallFdtFromHob ();

  return Status;
}
